[Fix] Do not set HTTP_RAW_POST_DATA if it cause String overflow

Summary:
In video upload, the amount of data can overflow a String and cause exception
to be throw. I made a change so that we don't store HTTP_RAW_POST_DATA when
this happens.

Test Plan:
make fast_tests
upload a large video in non-chunk mode and make sure no exception is thrown
at the end.

Reviewers: mwilliams, qigao

Reviewed By: mwilliams

CC: hphp-diffs@lists, ps, mwilliams

Differential Revision: 345263

src/runtime/base/server/http_protocol.cpp

@@ -161,14 +161,17 @@ void HttpProtocol::PrepareSystemVariables(Transport *transport,
       }
       CopyParams(request, g->GV(_POST));
       if (needDelete) {
-        if (RuntimeOption::AlwaysPopulateRawPostData) {
+        if (RuntimeOption::AlwaysPopulateRawPostData &&
+            size <= (int)StringData::LenMask) {
           g->GV(HTTP_RAW_POST_DATA) = String((char*)data, size, AttachString);
         } else {
           free((void *)data);
         }
       } else {
         // For literal we disregard RuntimeOption::AlwaysPopulateRawPostData
-        g->GV(HTTP_RAW_POST_DATA) = String((char*)data, size, AttachLiteral);
+        if (size <= (int)StringData::LenMask) {
+          g->GV(HTTP_RAW_POST_DATA) = String((char*)data, size, AttachLiteral);
+        }
       }
     }
   }